LAWRENCE — Four woman hired as receptionists at a massage parlor said the owner lured them into prostitution and forced them to continue under the threat of blackmail, according to prosecutors.

One of the alleged victims told authorities that the owner, Lori Barron, took videos of the women performing sex acts on clients and used the recordings to “threaten to fire them and expose them,” Assistant Essex District Attorney Kelleen Forlizzi said in court Tuesday.

“At one point, this defendant, Mrs. Barron, told the victim, ‘You have to do it,’ ” Forlizzi said.

Barron, 50, was arrested Monday at her house in Salem, N.H. Police searched her home and the massage studio at 7 Broadway in Lawrence, taking with them Barron’s laptop, another computer, two cellphones, and several files.

She allegedly kept detailed records on her clients, compiling a list that one of the alleged victims said contained the names of at least one city councilor, firefighters, police officers, doctors, and other prominent figures, Forlizzi said.

Authorities did not say where the clients were from or release any of their names.

Barron was charged in Lawrence District Court Tuesday with seven offenses, including deriving support from prostitution, extortion, human trafficking, unlawfully secretly recording persons in the nude, and witness intimidation.

Dressed in a black pants suit and pink blouse, Barron remained silent during her arraignment as her lawyer, Anthony Ortiz, entered a not-guilty plea on her behalf. Ortiz said the charges against his client are the result of “baseless allegations made by four disgruntled former employees.”

He said Barron “vehemently denies” all the charges. He said police searched her house and the massage studio and found no video equipment.

Barron was ordered held on $30,000 cash bail, which was later posted by her husband. She is due back in court on June 27 for a preliminary hearing.

Steve Barron, the defendant’s husband, would say only that “I completely stand behind my wife.” The couple have two daughters who are in college, Ortiz said.

Barron was convicted of prostitution in New Hampshire in 2011 after Salem police conducted an undercover operation at a spa she owned.

In the latest case, Lawrence Police Chief John Romero said the items taken from the home and studio were given to State Police to investigate. He said no officers from his department were ever clients.

Prosecutors said that Barron groomed her workers, paid them $1,000 a week as receptionists and promised substantially more income if they performed sexual acts on clients.

The customers put $100 in a basket upon arrival, of which $80 went to Barron and $20 to the employee providing the massage. Then, the customer would provide additional money, between $100 to $200, in a “tip basket” as payment for sex, according to prosecutors. The employee would keep most of that money, with Barron receiving a cut.

The workers were as young as 17, and some had children. Barron was characterized as a motherly figure who bought clothes for the women, but also as someone who used the threat of violence to keep the women subjugated.

On at least one occasion, in March, Barron attacked an employee who refused a client’s demand, authorities said. The employee called police.

According to the police report, Barron dragged the employee by her hair down two flights of stairs. “You just cost me money,” Barron allegedly yelled at the employee.